I remember meeting somebody at any electronic convention who told me that he used 24-bits ADCs in electronic balances, because it gave him effectively 14 bits with the 10 LSbs so wildly unstable that they were useless. Asked him why he did not use 14-bits ADC in the first place, he said that gave him just 12-bits, with the 2 LSbs unusable. He probably just didn't bother with the other factors while designing with ADCs, and threw in the biggest, bestest ADC that was out there hoping it would give him the bits needed even if this was half of what the ADC could do potentially.